Is there a reasonably straight-forward, repeatable, and consistent process to resize a bullet larger?

Resizing dies to size-down bullets are ubiquitous and produce good results. Is there anything similar to go the opposite direction? Does anyone have a process that they have used successfully?

Powder coating can make bullets slightly larger - .001 to .002.

Bumping up bullets is something that I have heard of but never tried. There is some info out there if you Google it.

For lead bullets yes. Readily available no! for jacketed bullets I have never heard of anything.

These are functions of the bullet swaging process. The expert for making your own swaged bullets is Corbin. Check with them, but understand nothing is inexpensive!

In the past I swaged down jacketed bullets from .338 to .330/.331 for 8x56R Hungarian. My homemade dies did real good on the diameter, but over half the bullets were banana shaped (and only good for shooting around corners)

Ivan

Give a little information. Are you talking about cast or jacketed bullets? Do you want to increase base/shank diameter, nose diameter, or both? What style bullet? How much of an increase are you looking for?

The cast bullet guys use bump dies to increase nose diameter of cast rifle bullets. I don't know about a jacketed bullet. If bullets of the proper diameter are available, this may be the most practical and cheapest way to go.

I have a boat load of .427 diameter 225 grain 44-40 bullets. They get "upsized" by melting and recast into .452 and .429 projectiles!

There are lots of sizes if you are talking about 9mm bullets
and the 38 and 45 that are made by a lot of people.

As mentioned.......
more info please.

I have found that water dropping cast bullets make them slightly larger. But no way to make them bigger post manufacture.

I've made some bullet moulds larger by lapping.

It is possible to "bump up" bullet diameters, as well as reforming specific portions of a bullet to different shapes or profiles. The requirements are a swaging die of the desired shape, diameter, etc, and a press capable of applying sufficient pressure (measured in multiples of tons) to force the projectile into the new form.

This is a gross simplification of the process, of course. Other factors that would come into play include the hardness of the projectile (both core and jacket, as applicable), with the harder materials having a tendency to fracture rather than flow under pressure, and limitations on the capabilities of die forms to both receive and form the piece while also allowing the resulting piece to be extracted without damage (lubricants may be useful, but may also adversely affect the forming process).

Swaged bullets have been in use for well over a century. One application was during the US Civil War with "picket rifles" (heavy rifles set up on posts or pickets and used for long range engagement of individual targets). These rifles utilized bullets made by casting an undersized slug of lead, then driving it into a swaging die to final form and diameter that precisely matched the bore and grooves of the rifle. Such rifles were very precisely made, no mass production was possible for the degree of accuracy required, and no commonality of parts was usually found, each rifle was delivered with an appropriate casting mold and swaging tool.

Modern swaged bullets include both jacketed and unjacketed types. Undersized pieces of pure lead (or very mile alloys) are formed under high pressures, then ejected from the forming dies (typically adjusted to carefully control final results to close tolerances of weight in addition to form and contours). When jackets are used they are typically slightly undersized cup-shaped pieces into which the lead core material is inserted, then the swaging process is done (frequently in multiple stages to achieve a final form). At least one maker (Speer) offers jacketed bullets with the interior of the jacket cups tinned with solder, then the lead core material inserted at or near liquid state, then swaged together resulting in a strong bond to hold the core and jacket together as one piece (the goal being to allow controlled expansion while keeping the bullet in one piece to enhance penetration).

Bullet swaging is a highly advanced aspect of the shooter and reloader sports. There have been any number of top-level competitors (particularly bench rest shooters) that have invested heavily in the equipment to create their own bullets to their own specifications. Demand for this type of equipment has steadily declined over the past 50 years or so as more sources of factory-made bullets of extremely high quality and consistency have become available to the general public.

The hobbyist will always be limited by budget and availability of a facility capable of operating the necessary machinery to produce consistent results. While a large manufacturer may have industrial space and expensive equipment, the home producer is probably limited in equipment and facilities.

It appears that the original poster may have lost interest in his thread.

Maybe he’s moved on to asking the folks on a carpentry thread about a saw to cut boards longer. The only serious answer we had for him was the one involving swaging undersized lead bullet to “bump them up” if he was talking about increasing the diameter of previously cast bullets.

Froggie